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By CLIFF BARNETT
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EIGHTEEN horsepower doesn't sound
very much for a light aeroplane. To fly
and stay airborne on "pony power"
usually means a "minimum" aeroplane
in just about every sense of the word
—low on performance, strength and
controllability.
A flyable design of this power that
performs as well as some conven
tional aircraft with several times the
horsepower is a real achievement and
not surprisingly it was the designer
of some of the most remarkable light
weight aircraft of the age, Burt Rutan,
who was its creator.
Rutan once described the Quickie
as "looking like a Staggerwing Beech
without a tail," although any com
parison between this tiny glassfibre
midget and Walter Beech's mighty
biplane really ends with the back-
staggered layout. Quickie both is and
isn't a biplane, because the "lower
wing" is a canard foreplane, bearing
elevators. The real wing, bearing a
pair of small inboard ailerons, is
shoulder-mounted halfway along the
fuselage. No horizontal surfaces are
needed at the tail, of course, and
originally the fin contained no rudder,
the idea being to attach a vane to
the steerable tailwheel. But this
turned out to be over-optimistic, and
there is now a small conventional
rudder mounted in the fin. With each
main-wheel mounted literally at the
tip of the foreplane, Quickie's chances
of surviving a groundloop must be
way above average for a taildragger.
Quickie was designed to provide
safety for the low-time pilot; easy,
quick construction by a first-time
homebuilder; and performance with a
capital P—100 m.p.h. and not far
short of 100 m.p.g. Success depended
from the beginning on the engine,
and two of Rutan's colleagues, Gene
Sheehan and Tom Jewett, started look
ing in 1975 for a reliable 12 h.p.
engine. They examined various two-
stroke and four-stroke engines used
in chainsaws, garden tractors, motor
cycles and cars, but nothing seemed
suitable: the light and powerful ones
were not sufficiently reliable, and the
reliable ones were either too heavy
or not powerful enough.
Two-strokes offer good power/
weight, and they are simple and often
cheap. But their disadvantages include
poor fuel economy, high r.p.m. and
vibration, fairly critical mixture set
tings, and dubious reliability. Four-
strokes, with their better fuel economy
and good reliability, are usually much
more preferable but low-power
engines tend to have a poor power/
weight ratio and run at high r.p.m. to
produce sufficient power. One engine